Digital video recorder

A hard disk recorder, and video disk recorder, a recorder, the video or audio is digital recording onto a hard drive. Most Set-Top-Boxen/Receiver have such a function, usually one speaks of PVR (Personal Video Recorder).

Functions

As a further development of the conventional video cassette recorder, the data - with the most used in the home video systems - similar stores on magnetic tape cassettes, the data is digitally, that is recorded on a standard in the computer art medium is a hard disk in the hard disk recorder. If no digital signal is supplied to or received, the hard disk recorder must convert the analog signal by means of a built-in analog / digital converter.

Thus stored on the hard drive recordings can be played back directly. Forward and rewind omitted and the quality remains the same even after repeated playing, as there are no signs of wear, as they are known from video tapes. With an additional DVD burner can be the data for archiving and exchange also burn to a DVD.

Timeshifting particular, usually called Timeshift, is a popular feature in hard disk recorders. The additional availability of an electronic program guide ( EPG) simplifies the selection of recorded broadcasts very.

Some devices have a slot for memory cards or a USB / eSata port on which you can play images, audio files, and often films and import to the hard drive in the PVR. Partially, but not for all devices, the USB port of the PVR allows you to record to an external storage medium and an export of the internal hard drive to an external storage medium.

Capacity and disk

Hard disk recorders have a recording capacity of up to several hundred hours depending on the capacity of the hard drive and the compression rate of the films.

The available recording capacity depends on the recording mode. Recorder, record the analog signals, they must digitize only. To increase the recording capacity, the compression may be greatly increased here, but this leads to a significant degradation of the image. If digital signals (DVB ) is recorded, it is stored directly without computational effort. This is in SD picture material about 1.5 to 3 GB of disk space per hour of video is (depending on the encoding of the TV station ), with HD recording, a film, depending on the quality of the broadcast, even 6-10 GB or more per hour take to court. Here, the size is even after the broadcast audio standards such as Dolby Digital or contained subtitles.

In the meantime ( as of October 2009 ) there is a wide range of DVB- disk recorders, even as multi-tuner with up to 6 DVB-S/DVB-S2 receivers simultaneously or mixed operation between different types of reception and a DVD or BR drive. Also for terrestrial reception (DVB -T) there are devices. Panasonic and Samsung also offer models with a DVD recorder for satellite reception ( DVB-S/DVB-S2 ). Also for digital cable (DVB -C), there are many devices, as well as for HD reception.

Available are integrated hard drives in the market sizes. Likewise recorders are offered with built - replaceable or mobile hard drives, nothing needs to be deleted. When the memory is full, you simply attach another hard drive. A few units even offer a streaming data without going directly to a server (NAS ) via the network interface.

Meanwhile, some manufacturers offer for such digital media devices optimized hard drives. These are usually the changed requirements in accordance with cooler, quieter, more energy efficient and especially to PC hard drives then optimized simultaneously accommodate several large and zeitvolumige data streams evenly and continuously and playback (streaming).

In addition to hard drives and USB sticks are often used as a medium. However, these are usually the preparation, slow, expensive, low-capacity and often do not allow for multiple shots or no shift when are they ever fast enough.

Also available are Blu- ray recorder, received the films and broadcasts in full HD quality, save and write to Blu -ray.

Formats of recording media

A certain problem is the necessary for the operation, basic formatting the hard disk of the unit, where they can bring may limitations.

The range of products extends over FAT32, Ext2, Ext3, JFS, NTFS, and up to house systems, depending on the manufacturer and operating system used. The recorded files are often split into multiple parts (ie dismembered saved ).

When outdated FAT32 file system for example, the system-dependent maximum file size of 4 GB. When copying a longer film on a PC is obtained as soon instead of a contiguous file multiple files. Therefore are recommended for receivers modern, full file systems, which are usually free of charge support of various operating systems.

However, some manufacturers split their recordings in any case, even if the file system used would allow larger files.

Personal Video Recorder (PVR)

A Personal Video Recorder (PVR) or English Personal Video Recorder [ pɜ ː sənəl vɪdiəʊ ɹɪkɔ ː də ] is a video recorder with a hard drive instead of the usual tape drive of the user's program preferences "remembers" and him on the hard drive ( a standard computer hard drive or a dedicated AV HDD ) offers a program stored in accordance with its interests, often in combination with time-shifted television, which allows the viewing of a program, even while it is still being recorded.

PVRs are usually offered with one or more DVB receivers, where the received DVB stream is stored unchanged on the disk. One equipment with two tuners ( twin tuner ) usually allows to watch a program while recording another, possibly, a second program to look as picture in picture, rarely, two different programs or program bundle take time. Equipping a DVB -PVR connected to an analog input ( Scart) allows not usually a recording from external sources, but only allows their looping on screens with too few inputs.

Some devices have also installed a DVD recorder to the hard disk. Depending on the device allows the DVD recorder a change memory as the recording media or an archive of posts that have been recorded on the hard disk. A cutting and dubbing of the stored transport stream to DVD can be realized much easier with such devices than to have to transfer the recorded movie, for example, only on a powerful PC, then edit it using special software to cut and there according to a program stream convert DVD specification and also to be provided with navigation aids for a DVD player and burn.

Internet -based PVR

In addition to stationary devices and the use of Internet-based video recorders is possible. The devices are available in a data center connected to the Internet and can be programmed by the user via the Internet. The recorded programs can be transferred immediately by streaming or by downloading either. The network recorder can record an unlimited number of programs simultaneously and gives its user the next time a spatial independence from the TV program.

Alternative: PC hard disk recorder

As an alternative to commercial prefabricated devices that are usually worse upgradeable, there is also a PC can be used as a recorder. Here one is also different hardware and software that can handle analog and those that record the digital input signals.

Analogous

• Hauppauge WinTV (Windows)
• Hauppauge HD PVR (Windows ), ( Mac OS X)
• Elgato EyeTV
• LinuxMCE (Linux)
• MediaPortal (Windows)
• MythTV (Linux, Mac OS X, BSD)
• Windows Media Center for Microsoft Windows XP, Microsoft Windows Vista, Microsoft Windows 7 and Microsoft Windows 8
• VDR (Linux)

Digital ( DVB)

• Hauppauge WinTV (Windows)
• Hauppauge HD PVR (Windows ), ( Mac OS X)
• DVBViewer (Windows)
• Elgato EyeTV ( for Macintosh only )
• Freevo
• LinuxMCE (Linux)
• MediaPortal (Windows)
• MythTV (Linux, Mac OS X, BSD)
• NMM
• Sceneo TVcentral (Windows)
• Tvoon Media Center (Windows)
• VDR (Linux)
• Windows Media Center for Microsoft Windows XP, Microsoft Windows Vista, Microsoft Windows 7 and Microsoft Windows 8
• Tvheadend (Linux)